On Thu, Jun 04, 2009 at 12:43:29AM +1000, Kel Modderman wrote: > CC'ing Roger. > > On Saturday 30 May 2009 21:49:16 Dmitry Maksyoma wrote: > > > > Just to let you know: when /etc/mtab is a symlink to /proc/mounts, loop > > devices > > aren't freed by umount and the system may run out of loop devices (which > > makes > > things worse than they were with old-style mtab). Apparently, it's not a > > bug, as > > it's documented in mount(8): > > > > If you are not so unwise as to make /etc/mtab a symbolic link to > > /proc/mounts > > then any loop device allocated by mount will be freed by umount. You can > > also free a loop device by hand, using `losetup -d', see losetup(8). > > > > Thanks for pointing it out Dmitry. > > Symlinking of mtab to /proc/mounts also seems to change/stop the user= mount > option from working properly.
I think this may be a red herring. The mount(8) manual page says a lot of incorrect things about missing information in /proc/mounts which is present in /etc/mtab. However, with a current kernel all of the information is there. If umount was failing due to insufficient information, this is a non- issue since all kernels from stable up support it. If umount behaves differently if /etc/mtab is a symlink, then that's a nasty bug in mount that needs fixing. It's probably a trivial fix to remove the special case handling of the symlink, if such a special case is present. > Do the benefits of symlinking mtab -> mounts outweigh possible regressions > related to loop device mounting or user= mount option? Yes. For all the reasons given in the report. Additionally, it fixes a *lot* of bugs in mount, where mount would royally screw up /etc/mtab when it got confused, or would misbehave due to having incomplete information in /etc/mtab. Things like "rbind" which are used far more commonly than "loop" are basically broken with /etc/mtab as a file. With /etc/mtab as a symlink, it always represents the current state of the system; it can't get out of date or corrupted. However, if Dmitry can confirm this is a real bug (as opposed to a documentation issue, in which case it still needs a bug against mount), then the solution is fixing mount rather than not fixing this bug. Regards, Roger -- .''`. Roger Leigh : :' : Debian GNU/Linux http://people.debian.org/~rleigh/ `. `' Printing on GNU/Linux? http://gutenprint.sourceforge.net/ `- GPG Public Key: 0x25BFB848 Please GPG sign your mail. -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
